Epidemiologic and Clinical Evaluation of Thyroid Cancer in Children from the Gomel Region (Belarus)

Abstract

This study reviews the epidemiology of thyroid cancer during childhood from the environs of Gomel in Belarus and the clinical data of 64 children aged 4 to 16 years from this area who had been diagnosed with differentiated thyroid carcinoma following the nuclear accident of Chernobyl. One case of thyroid cancer in children (aged < 15 years at diagnosis) was observed during the period 1981-1985 (rate = 0.5; expressed as annual averages per million children under age 15 years in the region of Gomel and period identified) before the Chernobyl accident. Twenty-one cases of thyroid cancer in children were observed during 1986-1990 (rate = 10.5) and 143 (rate 97) during 1991-1994 after the Chernobyl accident. During the first 7 months of 1995, there were 33 more cases of thyroid cancer observed in children. Three children with thyroid cancer were born since 1986 in the Gomel region. A total of 64 children aged 4 to 16 years from this area who had been diagnosed with differentiated thyroid carcinoma had been reviewed by us during the period May to November 1994. The female/male ratio was 1.4:1.0. At the time of the first diagnosis the mean age of the children was 9.4 +/- 2.8 years, and at the time of the accident their mean age was 3.8 +/- 2.4 years. More than 90% of the patients were less than 6 years of age and 3 were still in utero at the time of the accident. The period of latency between the accident and the first diagnosis was 5.6 +/- 1.5 years. Their ages at the time of the first diagnosis and their ages at the time of the accident were significantly correlated (p = 0.001); there was no significant correlation between the age of each child at the time of the accident and the latent period before the onset of carcinoma. The aggressiveness of the tumor, evaluated on the basis of T stage, lymph node status, and lung metastases, did not correlate with age at the time of the first diagnosis or with the age at the time of the accident. The susceptibility of the thyroid to the carcinogenetic effects of radiation, particularly during the first years of life (< 5 years) has clearly been demonstrated. However, there appears to be no correlation between the aggressiveness of the tumor and the age of the patients.

Growth and development after hematopoietic cell transplant in children

“…3 Studies from the Chernobyl accident indicate that children are much more susceptible to the carcinogenic effects of irradiation of the thyroid than older individuals. 4 Thus, children who have received TBI or TLI in their HCT preparative regimens are at risk for development of thyroid neoplasms.…”

FISH analysis of translocations in lymphocytes of children exposed to the Chernobyl fallout: preferential involvement of chromosome 10

“…A recent epidemio logical investigation showed a clear radiosensitivity of the thy roid gland in Belarus children after the Chernobyl nuclear fal lout occurred (Antonelli et al, 1996). The hypothesis that the radiosensitivity of the thyroid gland may be linked to the fragil ity of chromosome 10, which bears several genes involved in thyroid tumor initiation or progression (Bongarzone et al, 1994;Zedenius qt al" 1996), is attractive.…”

“…In addition, a significant increase in cancer incidence was detected in subjects having a high frequency of chromosome aberrations in somatic cells; as a consequence, the observed DNA damage may be considered an early indicator of cancer risk (The Nordic Study Group, 1990;Bonassi et al, 1995). In particular, thyroid cancer, predominantly of the papillary histotype, was seen to occur in Gomel (Belarus) children at a high er rate than normally expected (Kazakov et al, 1992;Antonelli et al. 1996).…”

Chronic graft-versus-host disease and late effects after hematopoietic stem cell transplantation

“…Many steps in the developmental pathway for malignant tumors remain elusive, but etiological factors have been~identŸ from the study of genetiexlisorders (Fanconi anemia, iatrogenie or inherited immunodeficiency) viral infeetions (Epstein-Barr virus), and epidemiological studies of survivors of Hiroshima, Nagaski and Chernobyl 9 nuclear exposure [120][121][122][123]. Initial preclinical marrow transplant studies in dogs and monkeys demonstrate that malignancies occur significantly more frequently in irradiated animals rescued with autologous or allogeneic marrow relative to non-transplant controls [124,125].…”